Diketopyrrolopyrroles

ABSTRACT

1,4-Diketopyrrolo[3,4-c]pyrroles of formula ##STR1## wherein R 1 , R 2 , R 3  and R 4  are each independently of one another hydrogen, Cl, Br, CH 3 , OCH 3 , CN or phenyl, and at least one of the substituents, R 1 , R 2 , R 3  and R 4  is a group 
     
         --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X 
    
     wherein 
     n is an integer from 2 to 12, and 
     p is an integer from 1 to 3, 
     X is a heterocyclic radical selected from the group consisting of imidazolyl, pyrazolyl, triazolyl, piperazinyl, pyridinyl, pyrrolyl, thiazolyl, oxazolyl, benzoxazolyl, indolyl, benzthiazolyl, benzimidazolyl, benzotriazolyl, morpholinyl, piperidinyl and pyrrolidinyl, which radical is unsubstituted or substituted by one or two methyl groups, or is a group 
     
         --NR.sub.5 R.sub.6 
    
     or 
     
         --N[(CH.sub.2).sub.n --NR.sub.5 R.sub.6 ].sub.2, wherein 
    
     R 5  and R 6  are each independently of the other hydrogen, C 1  -C 6  alkyl or C 5  -C 6  cycloalkyl. 
     Pigment compositions comprising a minor amount of said compounds and diketopyrrolopyrrole pigments have excellent rheological and coloristic properties, especially in paint systems and in printing inks.

The present invention relates to novel diketopyrrolopyrroles which aresubstituted by at least one aminoalkoxy radical, and to the use thereoffor enhancing the colouristic and rheological properties ofdiketopyrrolopyrrole pigments.

It is known that the properties of a pigment can be improved by additionthereto of a minor amount of a pigment which has been modified by theintroduction of appropriate substituents. Thus, for example, DE-OS 38 32064 discloses a process for the preparation of pigment compositionshaving enhanced colouristic and rheological properties by bead millinganthraquinone pigments in the presence of pigments which have beenmodified by substitution with specific aminoalkyl groups and which aredefined as dispersants. Pigments which are substituted by a heterocyclicradical bound through a methylene group and which have enhancedflocculation stability and rheological properties are disclosed in EP-A321 919. Diketopyrrolopyrrole compositions comprising adiketopyrrolopyrrole pigment and a minor amount of a modifieddiketopyrrole and having enhanced rheological properties are disclosedin U.S. Pat. No. 4,791,204. The modified diketopyrrolopyrroles are,inter alia, those which are substituted by cyclic carboxamide ordicarboxamide groups bound through a methylene group.Diketopyrrolopyrroles which are substituted by aminic radicals aredisclosed in JP Kokai 91-26767 as pigment dispersants which result inenhanced rheological properties. The aminic radicals, however, are notbound through an alkoxy bridge.

Novel diketopyrrolopyrroles which are substituted by at least oneaminoalkoxy radical have now been found which, admixed in a minor amountwith diketopyrrolopyrrole pigments, lead to surprisingly goodcolouristic and rheological properties, especially in paint systems andprinting inks.

Accordingly, the invention relates to 1,4-diketopyrrolo[3,4-c]pyrrolesof formula ##STR2## wherein R₁, R₂, R₃ and R₄ are each independently ofone another hydrogen, Cl, Br, CH₃, OCH₃, CN or phenyl, and at least oneof the substituents R₁, R₂, R₃ and R₄ is a group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

wherein

n is an integer from 2 to 12, and

p is an integer from 1 to 3,

X is a heterocyclic radical selected from the group consisting ofimidazolyl, pyrazolyl, triazolyl, piperazinyl, pyridinyl, pyrrolyl,thiazolyl, oxazolyl, benzoxazolyl, indolyl, benzthiazolyl,benzimidazolyl, benzotriazolyl, morpholinyl, piperidinyl andpyrrolidinyl, which radical is unsubstituted or substituted by one ortwo methyl groups, or is a group

    --NR.sub.5 R.sub.6

or

    --N[(CH.sub.2).sub.n --NR.sub.5 R.sub.6 ].sub.2, wherein

R₅ and R₆ are each independently of the other hydrogen, C₁ -C₆ alkyl orC₅ -C₆ cycloalkyl.

R₅ and R₆ defined as C₁ -C₆ alkyl may typically be methyl, ethyl,n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl andn-hexyl.

R₅ and R₆ defined as C₅ -C₆ cycloalkyl are cyclopentyl and, preferably,cyclohexyl.

Particularly interesting 1,4-diketopyrrolo[3,4-c]pyrroles of formula Iare those wherein at least one of R₁, R₂, R₃ or R₄ is a group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

wherein

n and p are as defined above, and X is a heterocyclic radical selectedfrom the group consisting of imidazolyl, pyrazolyl, triazolyl,piperazinyl, pyridinyl, pyrrolyl, thiazolyl, oxazolyl, morpholinyl,piperidinyl and pyrrolidinyl, or is a group

    --NR.sub.5 R.sub.6

wherein R₅ and R₆ are as defined above.

Preferred 1,4-diketopyrrolo[3,4-c]pyrroles of formula I are thosewherein one or two of R₁, R₂, R₃ or R₄ are a group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

wherein

n is an integer from 2 to 6 and

p is an integer from 1 or 2, and

X is a heterocyclic radical selected from the group consisting ofimidazolyl, pyrazolyl, triazolyl, piperazinyl, pyridinyl, pyrrolyl,thiazolyl, oxazolyl, morpholinyl, piperidinyl and pyrrolidinyl, or is agroup

    --NR.sub.5 R.sub.6

wherein R₅ and R₆ are each independently of the other hydrogen, methylor ethyl.

Most preferably, X is a heterocyclic radical selected from the groupconsisting of imidazolyl, pyrazolyl, morpholinyl, piperidinyl,pyrrolidinyl and triazolyl, or is a group --NR₅ R₆.

Particularly preferred 1,4-diketopyrrolo[3,4-c]pyrroles of formula I arethose wherein one of R₃ or R₄ is a group

    --O(CH.sub.2).sub.n NR.sub.5 R.sub.6 or --O(CH.sub.2).sub.n X

wherein n is an integer from 2 to 4 and R₅ and R₆ are identical and arehydrogen, methyl or ethyl, and X is morpholinyl, piperidinyl orpyrrolidinyl.

As already previously mentioned, the admixture of a minor amount of anovel diketopyrrolopyrrole of formula I with a diketopyrrolopyrrolepigment effects a quite surprising enhancement of the colouristic andrheological properties of this latter.

The invention accordingly further relates to pigment compositionscomprising

a) 80-99.9% by weight of at least one 1,4-diketopyrrolo[3,4-c]pyrrole offormula I, wherein R₁, R₂, R₃ and R₄ are each independently of oneanother hydrogen, Cl, Br, CH₃, OCH₃, CN or phenyl, and

b) 0.1-20% by weight of at least one 1,4-diketopyrrolo[3,4-c]pyrrole offormula I as defined in a) in which at least one of R₁, R₂, R₃ and R₄ isa group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

as defined above.

The diketopyrrolopyrroles of component a) of the novel compositions areknown compounds and can be conveniently prepared by the processesdescribed in U.S. Pat. Nos. 4,579,949 and 4,749,795.

The diketopyrrolopyrroles of formula I can be prepared by processesanalogous to standard known ones, typically by reacting a diester ofsuccinic acid with a nitrile or with a mixture of nitriles of formulae##STR3## as taught e.g. in U.S. Pat. Nos. 4,579,949 and 4,720,305, or,especially in the case of the preferred compounds of formula I, whereinone of R₃ or R₄ is a group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

by reacting a pyrrolinone of formula ##STR4## or an enamine of formula##STR5## with a nitrile or with a mixture of nitriles of formula III, asdisclosed e.g. in U.S. Pat. Nos. 4,659,775 and 4,749,795.

R₁, R₂, R₃ and R₄ in formulae II, III, IV and V are as defined above,with the proviso that at least one of said substituents, and preferablyone of R₃ and R₄, must be a group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

as defined above.

R in formulae IV and V is lower alkyl, typically methyl, ethyl,n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl and tert-amyl.Methyl and ethyl are preferred.

The compounds of formulae II, III, IV and V are known compounds. Anythat are novel can be prepared by methods analogous to standard knownones.

The pigment compositions can be conveniently prepared by the followingcommonly employed methods:

Direct in the synthesis by reacting a diester of succinic acid withdifferent nitriles of formulae II and III, as taught e.g. in U.S. Pat.No. 4,720,305, with the proviso that the nitrile not carrying the group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

(or the mixture of such nitriles) must be used in such excess over thenitrile (or the mixture of such nitriles) carrying at least one of saidgroups that the required ratio defined above of a) to b) is maintained.

By mixing components 1 and 2 described below.

Component 1 consists of at least one 1,4-diketopyrrolo-[3,4-c]-pyrrole,as defined in a).

Component 2 consists either of at least one1,4-diketopyrrolo[3,4-c]pyrrole as defined in b), or of a mixture of atleast one 1,4-diketopyrrolo[3,4-c]pyrrole as defined in a) and at leastone 1,4-diketopyrrolo[3,4-c]pyrrole as defined in b)

The two components 1 and 2 are mixed by any of the commonly employedmethods. Component 2 can be admixed conveniently as moist press cake oras powder during the synthesis, the recrystallisation or the filtrationof component 1 with this latter. Components 1 and 2 can also be mixed byintensive mixing or milling, or they can be added to the high molecularweight organic material to be coloured and mixed during the dispersionprocess.

The novel pigment compositions can be used as pigments for colouringorganic material of high molecular weight.

Illustrative examples of organic materials of high molecular weightwhich can be coloured with the novel pigment compositions are celluloseethers and esters, typically ethyl cellulose, nitrocellulose, celluloseacetate, cellulose butyrate, natural resins or synthetic resins,typically polymerisation or condensation resins, such as aminoplasts,preferably urea/formaldehyde and melamine/formaldehyde resins, alkydresins, phenolic plastics, polycarbonates, polyolefins, polystyrene,polyvinyl chloride, polytetrafluoroethylene, polyamides, polyurethanes,polyesters, polyether ketones, polyphenylene oxides, rubber, casein,silicone and silicone resins, singly or in mixtures.

The above high molecular weight organic compounds may be singly or asmixtures in the form of plastics, melts or of spinning solutions,paints, coating materials or printing inks. Depending on the end userequirement, it is expedient to use the pigments of the invention astoners or in the form of preparations. The pigments of the invention canbe used in an amount of 0.01 to 30% by weight, preferably 0.1 to 10% byweight, based on the high molecular weight organic material.

For pigmenting paints, coating materials and printing inks, the highmolecular weight organic materials and the pigments of the invention,together with optional additives such as filters, other pigments,siccatives or plasticisers, are finely dispersed or dissolved in acommon organic solvent or solvent mixture. The procedure may be suchthat the individual components by themselves, or also several jointly,are dispersed or dissolved in the solvent and thereafter all thecomponents are mixed.

The colourations obtained in plastics materials, fibres, paints systemsor printing inks have good allround fastness properties such as superiorcolour strength, good dispersibility, good fastness to overspraying,migration, heat, light and weathering, and they have low viscosity andgood gloss.

Furthermore, compared to unmodified base pigments, the novel pigmentcompositions have enhanced performance properties in application, suchas enhanced rheology and shelf life, lesser separation effects, such asfloating when concurrently using e.g. white pigments, and a lessertendency to flocculate. Owing to the good rheological properties ofthese compositions it is also possible to prepare coating materials andpaints systems with high loading. They are therefore preferably suitablefor colouring paints, especially for metal effect finishes.

The above described component 2 may, however, itself also be used aspigment for colouring the organic materials of high molecular weightcited previously. For this utility it can be used as crude product orafter appropriate conditioning/aftertreatment, conveniently as describedabove in connection with the novel pigment compositions.

The invention is illustrated by the following Examples.

EXAMPLE 1

2.3 g of sodium are stirred vigorously in 55 ml of refluxing tert-amylalcohol until complete dissolution. The temperature is lowered to95°-100° C., then 6.38 g of 4-[2-(dimethylamino)ethoxy]benzonitrile areadded, followed by the addition over 45 minutes of 7.73 g of thepyrrolinone of formula ##STR6## and stirring is continued for 2 hours at95°-100° C. The reaction mixture is then cooled to 40° C. and pouredinto a stirred solution of 6.7 g of acetic acid in 500 ml of methanol.The crude product so obtained is isolated by filtration, washed withmethanol and then with water and dried overnight at 90° C. Yield: 8.41 g(67% of theory) of the product of formula ##STR7## in the form of ayellowish-red powder.

Analysis: calcd: C 70.38% H 5.64% N 11.19%; found: C 70.11% H 5.64% N11.17%.

EXAMPLE 2

In a sulfonating flask, 17.2 g of3.6-diphenyl-1,4-diketopyrrolo[3,4-c]pyrrole is stirred as moist presscake (29.1%; 5.0 g of solids) in 100 ml of deionised water for 1 hour atroom temperature. Then 0.24 g of the compound obtained in Example 1 isadded as moist press cake (54%; 0.13 g of solids), and the suspension isstirred for 2 hours at room temperature and then filtered. The filtercake is dried under vacuum at 80° C., giving 5.2 g of a red pigment.

EXAMPLE 3

35 ml of dry tert-amyl alcohol and 1.38 g of sodium are charged to a 100ml sulfonating flask and thoroughly mixed at 105° C. with efficientstirring for 17 hours until the sodium is completely reacted. Then 4.9 gof 4-(3-dimethylaminopropoxy)benzonitrile and 2.6 g of benzonitrile areadded, followed by the dropwise addition over 80 minutes of 4.5 g ofdiisopropyl succinate. The reaction mixture is stirred for 2 hours at110° C., then cooled to room temperature and charged to a cooled mixtureof 0° C. of 70 ml of methanol/water 1:1 (vol.) and 3.43 ml of aceticacid in a 350 ml sulfonating flask. The mixture is stirred for 2 hoursat room temperature, filtered, and the residue is washed with methanoland water and dried at 90° C. in a vacuum oven to give a dark redpigment. The following data are obtained by mass spectroscopic analysis(FD): m/e 288, 389, 490.

EXAMPLES 4-16

The procedure of Example 3 is repeated, using equivalent amounts of thecorresponding nitriles to give the compounds listed in Table 1.

                                      TABLE 1                                     __________________________________________________________________________     ##STR8##                                                                     Ex-                                                                           ample                                                                             A        B                            Mass spectrum                       __________________________________________________________________________     4                                                                                 ##STR9##                                                                               ##STR10##                   .sup.m /.sub.e                                                                   288, 431                                                                             (EI)                       5                                                                                 ##STR11##                                                                              ##STR12##                   .sup.m /.sub.e                                                                   288, 423, 425                                                                        (EI)                       6                                                                                 ##STR13##                                                                              ##STR14##                   .sup.m /.sub.e                                                                   288, 440, 592                                                                        (FD)                       7                                                                                 ##STR15##                                                                              ##STR16##                   .sup.m /.sub.e                                                                   356, 474, 592                                                                        (FD)                       8                                                                                 ##STR17##                                                                              ##STR18##                   .sup.m /.sub.e                                                                   288, 375, 462                                                                        (M.sup.-) (CI,                                                                NH.sub.3)                  9                                                                                 ##STR19##                                                                              ##STR20##                   .sup.m /.sub.e                                                                   357, 410, 463                                                                        (M + H).sup.+  (CI,                                                           NH.sub.3)                 10                                                                                 ##STR21##                                                                              ##STR22##                   .sup.m /.sub.e                                                                   288, 431, 574                                                                        (FD)                      11                                                                                 ##STR23##                                                                              ##STR24##                   .sup.m /.sub.e                                                                   356, 465, 574                                                                        (FD)                      12                                                                                 ##STR25##                                                                              ##STR26##                   .sup.m /.sub.e                                                                   288, 429, 570                                                                        (FD)                      13                                                                                 ##STR27##                                                                              ##STR28##                   .sup.m /.sub.e                                                                   288, 560, 831                                                                        (FD)                      14                                                                                 ##STR29##                                                                              ##STR30##                   .sup.m /.sub.e                                                                   288, 419, 550                                                                        (FD)                      15                                                                                 ##STR31##                                                                              ##STR32##                   .sup.m /.sub.e                                                                   288, 473, 658                                                                        (EI)                      16                                                                                 ##STR33##                                                                              ##STR34##                   .sup.m /.sub.e                                                                   288, 444                                                                             (EI)                      __________________________________________________________________________     EI = Electron Impact                                                          FD = Field Desorption                                                         CI = Chemical Ionisation                                                 

EXAMPLES 17 AND 18

The procedure of Example 3 is repeated such that in each case only onenitrile (corresponding to the radicals A in Table 2) is used, but intwice the equivalent amount, to give the compounds listed in Table 2.

                                      TABLE 2                                     __________________________________________________________________________     ##STR35##                                                                                            Elemental analysis                                                            calculated                                                                              found                                       Example                                                                            A                  C  H   N  C  H   N                                    __________________________________________________________________________    17                                                                                  ##STR36##         67.51                                                                            6.54                                                                              12.11                                                                            65.42                                                                            6.67                                                                              7.90                                 18                                                                                  ##STR37##         68.55                                                                            6.99                                                                              11.42                                                                            68.14                                                                            7.15                                                                              10.96                                __________________________________________________________________________

EXAMPLE 19

To determine the flow properties, the pigment treated as described inExample 2 is incorporated by a standard method into an alkyd paintsystem (®SETAL 84, Kunstharzfabrik Synthesis B. V., Holland; solidscontent: 70% by weight).

The flow properties of the paint formulation which contains 12% byweight of pigment and 54% by weight of total solids and the totalpigment/binder ratio of which is 0.3, are determined with a HAAKE®ROTO-VISCO RV 12 viscosimeter (measuring temperature: 25° C., measuringsystem: SV-SP, shear range: D=0-100 [1/s]).

Compared to untreated 3,6-diphenyl-1,4-diketopyrrolo[3,4-c]pyrrole, thered pigment obtained according to Example 2 has enhanced rheologicalproperties in addition to excellent colouristic properties.

EXAMPLE 20

An offset printing ink is prepared on a three-roll mill by the method ofDIN 53 238-12 with the pigment treated according to Example 2, namelywith

20 parts of pigment and

80 parts of varnish comprising

50% parts by weight of oil-modified phenolic varnish (®ALVCO 1407)

32% parts by weight of terephthalic acid alkyd-linseed oil resin (100%solids content; ®TERLON 3)

18% parts by weight of mineral oil (boiling range 157°-214° C.; ®SUNOCOOIL).

The printing ink so obtained has excellent rheological properties andthe prints produced therewith on art paper have surprisingly goodcolouristic properties (strong red shade).

What is claimed is:
 1. A 1,4-diketopyrrolo[3,4-c]pyrrole of formula##STR38## wherein R₁, R₂, R₃ and R₄ are each independently of oneanother hydrogen, Cl, Br, CH₃, OCH₃, CN or phenyl, and at least one ofthe substituents R₁, R₂, R₃ and R₄ is a group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

wherein n is an integer from 2 to 12, and p is an integer from 1 to 3, Xis a heterocyclic radical selected from the group consisiting ofpiperazinyl, pyridinyl, morpholinyl, piperidinyl and pyrrolidinyl, whichradical is unsubstituted or substituted by one or two methyl groups, oris a group

    --NR.sub.5 R.sub.6

or

    --N[(CH.sub.2).sub.n --NR.sub.5 R.sub.6 ].sub.2, wherein

R₅ and R₆ are each independently of the other hydrogen, C₁ -C₆ alkyl orC₅ -C₆ cycloalkyl.
 2. A 1,4-diketopyrrolo[3,4-c]pyrrole of formula Iaccording to claim 1, wherein at least one of R₁, R₂, R₃ or R₄ is agroup

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

wherein n and p are as defined in claim 1, and X is a heterocyclicradical selected from the group consisting of piperazinyl, pyridinyl,morpholinyl, piperidinyl and pyrrolidinyl, or is a group

    --NR.sub.5 R.sub.6

wherein R₅ and R₆ are as defined in claim
 1. 3. A1,4-diketopyrrolo[3,4-c]pyrrole of formula I according to claim 1,wherein one or two of R₁, R₂, R₃ or R₄ are a group

    --O(CH.sub.2).sub.n X or --O(CH.sub.2 CH.sub.2 O).sub.p CH.sub.2 CH.sub.2 X

wherein n is an integer from 2 to 6 and p is an integer from 1 or 2, andX is a heterocyclic radical selected from the group consisting ofpiperazinyl, pyridinyl, morpholinyl, piperidinyl and pyrrolidinyl, or isa group

    --NR.sub.5 R.sub.6

wherein R₅ and R₆ are each independently of the other hydrogen, methylor ethyl.
 4. A 1,4-diketopyrrolo[3,4-c]pyrrole according to claim 3,wherein X is a heterocyclic radical selected from the group consistingof morpholinyl, piperidinyl and pyrrolidinyl or is a group --NR₅ R₆,wherein R₅ and R₆ are as defined in claim
 3. 5. A1,4-diketopyrrolo[3,4-c]pyrrole 3 of formula I according to claim 3,wherein one of R₃ or R₄ is a group

    --O(CH.sub.2).sub.n NR.sub.5 R.sub.6 or --O(CH.sub.2).sub.n X

wherein n is an integer from 2 to 4 and R₅ and R₆ are identical and arehydrogen, methyl or ethyl, and X is morpholinyl, piperidinyl orpyrrolidinyl.